<template>
  <div class="course">
    <Header></Header>
    <div class="main">
      <!-- 筛选条件 -->
      <div class="condition">
        <ul class="cate-list">
          <li class="title">课程分类:</li>
          <li @click="category=0" :class="category==0?'this':''">全部</li>
          <li @click="category=cat.id" :class="category==cat.id?'this':''" v-for="cat in category_list">{{cat.name}}</li>
        </ul>

        <div class="ordering">
          <ul>
            <li class="title">筛&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;选: </li>
            <li @click="change_order_type('id')" class="default" :class="change_order_class('id')">默认</li>
            <li @click="change_order_type('students')" class="hot" :class="change_order_class('students')">人气</li>
            <li @click="change_order_type('price')" class="price" :class="change_order_class('price')">价格</li>

<!--            <li @click="filters.type=0" class="default" :class="filters.type==0?'this':''">默认</li>-->
<!--            <li @click="filters.type=1" class="hot" :class="filters.type==1?'this':''">人气</li>-->
<!--            <li @click="filters.type=2" class="price" :class="filters.type==2?'this':''">价格</li>-->
          </ul>
          <p class="condition-result">共21个课程</p>
        </div>

      </div>
      <el-pagination
      background
      layout="prev, pager, next,sizes"
      :page-size="filters.size"
      :page-sizes="[2, 3, 5, 10]"
      @current-change="handleCurrentChange"
      @size-change="handleSizeChange"
      :total="total">
    </el-pagination>
      <!-- 课程列表 -->
      <div class="course-list">
        <div class="course-item" v-for="course in course_list">
          <div class="course-image">
            <img :src="course.course_img" alt="">
          </div>
          <div class="course-info">
            <h3><router-link :to="'/courses/detail/'+course.id">{{course.name}}</router-link> <span><img src="/static/image/avatar1.svg" alt="">{{course.students}}人已加入学习</span></h3>
            <p class="teather-info">{{course.teacher.name}} {{course.teacher.signature}} {{course.teacher.title}} <span>共{{course.lessons}}课时/{{course.pub_lessons==course.lessons?'更新完成':`已更新${course.pub_lessons}课时`}}</span></p>
            <ul class="lesson-list">
              <li :key="key" v-for="(lesson,key) in course.lessons_list"><span class="lesson-title">0{{key}} | 第{{lesson.lesson}}节：{{lesson.name}}</span> <span class="free" v-if="lesson.free_trail">免费</span></li>
<!--              <li><span class="lesson-title">01 | 第1节：初识编码初识编码</span> <span class="free">免费</span></li>-->
<!--              <li><span class="lesson-title">01 | 第1节：初识编码</span> <span class="free">免费</span></li>-->
<!--              <li><span class="lesson-title">01 | 第1节：初识编码初识编码初识编码初识编码</span> <span class="free">免费</span></li>-->
            </ul>
            <div class="pay-box">
              <span class="discount-type">限时免费</span>
              <span class="discount-price">￥0.00元</span>
              <span class="original-price">原价：{{course.price}}元</span>
              <span class="buy-now">立即购买</span>
            </div>
          </div>
        </div>
      </div>
    </div>
    <el-pagination
      background
      layout="prev, pager, next,sizes"
      :page-size="filters.size"
      :page-sizes="[2, 3, 5, 10]"
      @current-change="handleCurrentChange"
      @size-change="handleSizeChange"
      :total="total">
    </el-pagination>
    <Footer></Footer>
  </div>
</template>

<script>
  import Header from "./common/Header"
  import Footer from "./common/Footer"
  export default {
      name: "Course",
      data(){
        return{
          category: 0,
          category_list:[],
          total: 0,
          course_list: [],
          filters:{
              type: "id", // 筛选类型，id表示默认，students表示人气,price表示价格
              orders: "desc",  // 排序类型[控制样式]，desc表示降序，asc表示升序
              size: 5, // 单页数据量
              page: 1, // 当前页码
          }
        }
      },
      watch:{
          category(){
              this.get_course();
          }
      },
      created(){
        this.get_course_category();
        this.get_course();
      },
      methods:{
        get_course_category(){
            // 获取课程分类信息
            this.$axios.get(`${this.$settings.HOST}/course/category/`).then(response=>{
                this.category_list = response.data;
            })
        },
        get_course(){
            let filters = {
                page: this.filters.page,
                size: this.filters.size,
            };

            if(this.filters.orders==="desc"){
                filters.ordering = "-"+this.filters.type;
            }else{
                filters.ordering = this.filters.type;
            }
            // 判断是否要根据分类显示课程信息
            if( this.category > 0 ){
                filters.course_category = this.category;
            }

            this.$axios.get(`${this.$settings.HOST}/course/`,{
                params:filters
            }).then(response=>{
                this.course_list = response.data.results;
                this.total = response.data.count;
            });
        },
        change_order_type(type){
            // 更改升序或者降序
            if( this.filters.type === type && this.filters.orders === "desc" ){
                this.filters.orders="asc";
            }else if( this.filters.type === type && this.filters.orders === "asc"){
                this.filters.orders="desc";
            }

            // 更改排序方式
            this.filters.type=type;
            // 重新获取课程
            this.get_course();
        },
        change_order_class(type){
            // 更改当前选中筛选条件的高亮方式
            if( this.filters.type === type && this.filters.orders === "asc" ){
              return "this asc";
            }else if(this.filters.type===type && this.filters.orders === "desc"){
              return "this desc";
            }else{
              return "";
            }
        },
        handleCurrentChange(page){
            // 切换页码时，重新获取课程
            console.log("本次点击的页码是:", page);
            this.filters.page = page;
            this.get_course();
        },
        handleSizeChange(size){
            // 切换单页显示的数据量
            this.filters.size = size;
            // 重置页码
            this.filters.page = 1;
            this.get_course();
        },
      },
      components:{
        Header,
        Footer,
      }
  }
</script>



<style scoped>
  .course{
    background: #f6f6f6;
  }
  .course .main{
    width: 1100px;
    margin: 35px auto 0;
  }
  .course .condition{
    margin-bottom: 35px;
    padding: 25px 30px 25px 20px;
    background: #fff;
    border-radius: 4px;
    box-shadow: 0 2px 4px 0 #f0f0f0;
  }
  .course .cate-list{
    border-bottom: 1px solid #333;
    border-bottom-color: rgba(51,51,51,.05);
    padding-bottom: 18px;
    margin-bottom: 17px;
  }
  .course .cate-list::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .cate-list li{
    float: left;
    font-size: 16px;
    padding: 6px 15px;
    line-height: 16px;
    margin-left: 14px;
    position: relative;
    transition: all .3s ease;
    cursor: pointer;
    color: #4a4a4a;
    border: 1px solid transparent; /* transparent 透明 */
  }
  .course .cate-list .title{
    color: #888;
    margin-left: 0;
    letter-spacing: .36px;
    padding: 0;
    line-height: 28px;
  }
  .course .cate-list .this{
    color: #ffc210;
    border: 1px solid #ffc210!important;
    border-radius: 30px;
  }
  .course .ordering::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .ordering ul{
    float: left;
  }
  .course .ordering ul::after{
    content:"";
    display: block;
    clear: both;
  }
  .course .ordering .condition-result{
    float: right;
    font-size: 14px;
    color: #9b9b9b;
    line-height: 28px;
  }
  .course .ordering ul li{
    float: left;
    padding: 6px 15px;
    line-height: 16px;
    margin-left: 14px;
    position: relative;
    transition: all .3s ease;
    cursor: pointer;
    color: #4a4a4a;
  }
  .course .ordering .title{
    font-size: 16px;
    color: #888;
    letter-spacing: .36px;
    margin-left: 0;
    padding:0;
    line-height: 28px;
  }
  .course .ordering .this{
    color: #ffc210;
    position: relative;
  }
  .course .ordering .this::before,
  .course .ordering .this::after{
    cursor: pointer;
    content:"";
    display: block;
    width: 0px;
    height: 0px;
    border: 5px solid transparent;
    position: absolute;
    right: 0;
  }
  .course .ordering .this::before{
    border-bottom: 5px solid #aaa;
    margin-bottom: 2px;
    top: 2px;
  }
  .course .ordering .this::after{
    border-top: 5px solid #aaa;
    bottom: 2px;
  }
  .course .ordering .asc::before{
    border-bottom-color: #ffc210;
  }
  .course .ordering .desc::after{
    border-top-color: #ffc210;
  }
  .course .course-item:hover{
    box-shadow: 4px 6px 16px rgba(0,0,0,.5);
  }
  .course .course-item{
    width: 1050px;
    background: #fff;
    padding: 20px 30px 20px 20px;
    margin-bottom: 35px;
    border-radius: 2px;
    cursor: pointer;
    box-shadow: 2px 3px 16px rgba(0,0,0,.1);
    /* css3.0 过渡动画 hover 事件操作 */
    transition: all .2s ease;
  }
  .course .course-item::after{
    content:"";
    display: block;
    clear: both;
  }
  /* 顶级元素 父级元素  当前元素{} */
  .course .course-item .course-image{
    float: left;
    width: 423px;
    height: 210px;
    margin-right: 30px;
  }
  .course .course-item .course-image img{
    width: 100%;
  }
  .course .course-item .course-info{
    float: left;
    width: 596px;
  }
  .course-item .course-info h3 {
    font-size: 26px;
    color: #333;
    font-weight: normal;
    margin-bottom: 8px;
  }
  .course-item .course-info h3 span{
    font-size: 14px;
    color: #9b9b9b;
    float: right;
    margin-top: 14px;
  }
  .course-item .course-info h3 span img{
      width: 11px;
      height: auto;
      margin-right: 7px;
  }
  .course-item .course-info .teather-info{
      font-size: 14px;
      color: #9b9b9b;
      margin-bottom: 14px;
      padding-bottom: 14px;
      border-bottom: 1px solid #333;
      border-bottom-color: rgba(51,51,51,.05);
  }
  .course-item .course-info .teather-info span{
      float: right;
  }
  .course-item .lesson-list::after{
      content:"";
      display: block;
      clear: both;
  }
  .course-item .lesson-list li {
    float: left;
    width: 44%;
    font-size: 14px;
    color: #666;
    padding-left: 22px;
    /* background: url("路径") 是否平铺 x轴位置 y轴位置 */
    background: url("/static/image/play-icon-gray.svg") no-repeat left 4px;
    margin-bottom: 15px;
  }
  .course-item .lesson-list li .lesson-title{
      /* 以下3句，文本内容过多，会自动隐藏，并显示省略符号 */
      text-overflow: ellipsis;
      overflow: hidden;
      white-space: nowrap;
      display:inline-block;
      max-width: 200px;
  }
  .course-item .lesson-list li:hover{
      background-image: url("/static/image/play-icon-yellow.svg");
      color: #ffc210;
  }
  .course-item .lesson-list li .free{
      width: 34px;
      height: 20px;
      color: #fd7b4d;
      vertical-align: super;
      margin-left: 10px;
      border: 1px solid #fd7b4d;
      border-radius: 2px;
      text-align: center;
      font-size: 13px;
      white-space: nowrap;
  }
  .course-item .lesson-list li:hover .free{
      color: #ffc210;
      border-color: #ffc210;
  }
  .course-item .pay-box::after{
    content:"";
    display: block;
    clear: both;
  }
  .course-item .pay-box .discount-type{
    padding: 6px 10px;
    font-size: 16px;
    color: #fff;
    text-align: center;
    margin-right: 8px;
    background: #fa6240;
    border: 1px solid #fa6240;
    border-radius: 10px 0 10px 0;
    float: left;
  }
  .course-item .pay-box .discount-price{
    font-size: 24px;
    color: #fa6240;
    float: left;
  }
  .course-item .pay-box .original-price{
    text-decoration: line-through;
    font-size: 14px;
    color: #9b9b9b;
    margin-left: 10px;
    float: left;
    margin-top: 10px;
  }
  .course-item .pay-box .buy-now{
    width: 120px;
    height: 38px;
    background: transparent;
    color: #fa6240;
    font-size: 16px;
    border: 1px solid #fd7b4d;
    border-radius: 3px;
    transition: all .2s ease-in-out;
    float: right;
    text-align: center;
    line-height: 38px;
  }
  .course-item .pay-box .buy-now:hover{
    color: #fff;
    background: #ffc210;
    border: 1px solid #ffc210;
  }
  .el-pagination{
  text-align: center;
    padding-top: 20px;
    padding-bottom: 50px;
  }
</style>
